How would you approach a shader for a glittery eyeshadow
A good way to approach a glittery material that I've found works well is using voronoi cell noise as an input for a normal map:


By changing the strength of the normal map, you can change how non-flat the glitter effect is, and the size with the Voronoi scale.

If the object will be moving or animated, it would be recommended to plug a UV Map Node into the Voronoi Texture

Here's an example node setup with some basic blending via vertex color:



This method also works great for snow, car paint, and anything else that has a glitter to it!